US4725482A - Perpendicular magnetic recording medium - Google Patents

Perpendicular magnetic recording medium Download PDF

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Publication number
US4725482A
US4725482A US06/685,838 US68583884A US4725482A US 4725482 A US4725482 A US 4725482A US 68583884 A US68583884 A US 68583884A US 4725482 A US4725482 A US 4725482A
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US
United States
Prior art keywords
film
recording medium
perpendicular magnetic
chromium oxide
magnetic recording
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Expired - Fee Related
Application number
US06/685,838
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English (en)
Inventor
Tomohisa Komoda
Mamoru Ishizuka
Shuhei Tsuchimoto
Mitsuhiko Yoshikawa
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Sharp Corp
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Sharp Corp
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Assigned to SHARP KABUSHIKI KAISHA reassignment SHARP KABUSHIKI KAISHA ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: ISHIZUKA, MAMORU, KOMODA, TOMOHISA, TSUCHIMOTO, SHUHEI, YOSHIKAWA, MITSUHIKO
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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/64—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent
    • G11B5/65—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent characterised by its composition
    • G11B5/656—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent characterised by its composition containing Co
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/72—Protective coatings, e.g. anti-static or antifriction
    • G11B5/726—Two or more protective coatings
    • G11B5/7262—Inorganic protective coating
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00—Stock material or miscellaneous articles
    • Y10S428/90—Magnetic feature
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24942—Structurally defined web or sheet [e.g., overall dimension, etc.] including components having same physical characteristic in differing degree
    • Y10T428/2495—Thickness [relative or absolute]
    • Y10T428/24967—Absolute thicknesses specified
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24942—Structurally defined web or sheet [e.g., overall dimension, etc.] including components having same physical characteristic in differing degree
    • Y10T428/2495—Thickness [relative or absolute]
    • Y10T428/24967—Absolute thicknesses specified
    • Y10T428/24975—No layer or component greater than 5 mils thick
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/26—Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
    • Y10T428/263—Coating layer not in excess of 5 mils thick or equivalent
    • Y10T428/264—Up to 3 mils
    • Y10T428/265—1 mil or less

Definitions

  • the present invention relates to a perpendicular magnetic recording medium.
  • the perpendicular magnetic recording medium has been developed which forms residual magnetization in a direction perpendicular to the surface of the recording medium.
  • the perpendicular magnetic recording medium ensures high recording density.
  • the conventional perpendicular magnetic recording medium generally includes a film base or an aluminum base, and a Co-Cr film formed on the base by a sputtering method or an electron beam evaporation (E.B. evaporation) method.
  • E.B. evaporation electron beam evaporation
  • the conventional perpendicular magnetic recording medium does not have a smooth slide against a magnetic head.
  • the perpendicular magnetic recording medium and/or the magnetic head is damaged during operation, and the conventional perpendicular magnetic recording medium does not have a desirable durability.
  • a protective layer such as a Ni-P film, SiO film, SiO 2 film or a noble metal (Au, Rh, Pt, Ag, etc.) film is formed on the Co-Cr metal thin-film through the use of, for example, a plating method, a sputtering method, or an evaporation method.
  • the protective layer can alternatively be an oxide layer or a nitride layer formed on the Co-Cr metal thin-film, or an organic silicon compound film painted on the Co-Cr metal thin-film.
  • a suitable thickness for the protective layer is difficult to determine in the conventional perpendicular magnetic recording medium.
  • the protective layer creates a spacing loss which reduces the recording density, and deteriorates the reproduction output. If the protective layer is thin, the recording density can be enhanced, but the perpendicular magnetic recording medium and/or the magnetic head is damaged during operation, and the perpendicular magnetic recording medium does not have a satisfactory durability.
  • an object of the present invention is to provide a novel perpendicular magnetic recording medium which ensures a high density recording, and has a satisfactory durability.
  • Another object of the present invention is to provide a protective layer on a Co-Cr metal thin-film, which ensures a high density recording, and a smooth relative movement between the perpendicular magnetic recording medium and a magnetic head.
  • a Co-Cr perpendicular magnetic film is formed on a substrate by an RF-sputtering method.
  • a chromium oxide film is formed on the Co-Cr perpendicular magnetic film to a thickness of about 50 ⁇ by performing a heating treatment to the surface of the Co-Cr perpendicular magnetic film for two hours in an oxygen atmosphere of 10 -4 through 10 -3 Torr and temperature of 300° C. through 400° C.
  • a SiO 2 film of about 200 ⁇ thick is formed on the chromium oxide film. The total thickness of the chromium oxide film and the SiO 2 film is thin enough to ensure high density recording, and the chromium oxide film and the SiO 2 film function, in combination, to protect the Co-Cr perpendicular magnetic film from being damaged.
  • FIG. 1 is a sectional view of an essential part of an embodiment of a perpendicular magnetic recording medium of the present invention.
  • FIG. 2 is a graph for explaining recording density characteristics of the perpendicular magnetic recording medium of FIG. 1.
  • a perpendicular magnetic recording medium of the present invention includes a substrate 1 such as a film base or an aluminum base.
  • a Co-Cr perpendicular magnetic film 2 is formed on the substrate 1 by, for example, RF-sputtering.
  • a chromium oxide film 3 is formed on the Co-Cr perpendicular magnetic film 2 by conducting a heat treatment to the surface of the Co-Cr perpendicular magnetic film 2. The heat treatment is conducted in an oxygen atmosphere of 10 -4 through 10 -3 Torr and at a temperature of 300° C. to 400° C. for about two hours.
  • the chromium oxide film 3 has a thickness of about 50 ⁇ .
  • a SiO 2 film 4 of about 200 ⁇ thick is formed on the chromium oxide film 3 for protection purposes.
  • Perpendicular magnetic recording mediums A, B, C and D have SiO 2 layers of different thicknesses, but do not have the chromium oxide layer formed by the heat treatment.
  • the perpendicular magnetic recording medium E has the chromium oxide layer, but does not have the SiO 2 protective layer.
  • the perpendicular magnetic recording medium F is the embodiment of the present invention which has been described above with reference to FIG. 1.
  • the "Envelope” means the variation of the condition of the peak value of a reproduction signal obtained from the magnetic head.
  • the term “Good Envelope” means a stable peak value of a reproduction signal, that is, stable reproduction operation.
  • the recording medium A having the SiO 2 protective layer of a thickness of 1000 ⁇ ensures a stable reproduction operation even after 400,000 passes of the magnetic head travel.
  • the recording medium C having a thin SiO 2 protective layer and the recording medium D having no SiO 2 protective layer do not show a smooth traveling of the magnetic head on the perpendicular magnetic recording medium. It is assumed that, when the heating treatment has not been conducted to the Co-Cr perpendicular magnetic film, the SiO 2 protective layer must be thicker than about 700 ⁇ in order to obtain a desirable durability.
  • the recording medium E to which the heating treatment has been conducted but which does not have the SiO 2 protective layer generates the sliding noise when the magnetic head slides on the surface of the recording medium E, and the envelope of the reproduced signal is deteriorated as the reproduction operation is repeatedly conducted. That is, the chromium oxide film alone does not provide a desirable durability.
  • the recording medium F of the present invention does not generate the sliding noise, does not permit any damages to the magnetic head and the recording medium, and ensures a good envelope for a long time even though the SiO 2 protective layer is considerably thin. Further, the recording medium F shows a similar durability as the recording medium A. It is assumed that the chromium oxide layer and the SiO 2 protective layer function, in combination, to ensure stable operation.
  • the recording density of the recording medium F of the present invention is compared with the recording density of the recording medium A, which does not have the chromium oxide layer, through the use of a ring head of the gap length 0.7 ⁇ m.
  • a curve (1) represents the recording density characteristic of the recording medium F of the present invention
  • a curve (2) represents the recording density characteristic of the recording medium A.
  • the recording medium F of the present invention has a similar durability as the recording medium A. Further, the recording characteristic of the recording medium F of the present invention is superior to that of the recording medium A.
  • the chromium oxide layer should have a thickness between 20 through 200 ⁇ .
  • the SiO 2 protective layer must be thicker than 50 ⁇ , and the total thickness of the chromium oxide layer and the SiO 2 protective layer should be selected between 70 ⁇ and 300 ⁇ .
  • the SiO 2 protective layer and the chromium oxide layer provide, in combination, a good durability.
  • the total thickness of the chromium oxide and the SiO 2 protective layer is thin enough to minimize the spacing loss and to ensure a high recording density and a good reproduction characteristic.
  • the proteclayer can be a SiO film, or a Si 3 N 4 film.
  • the recording density of the recording medium is influenced by the perpendicular magnetic anisotropy of the Co-Cr perpendicular magnetic layer.
  • the present inventors have discovered that the perpendicular magnetic anisotropy of the Co-Cr film is enhanced when the chromium oxide layer is formed on the surface of the Co-Cr perpendicular magnetic film.
  • the function of the chromium oxide layer formed on the Co-Cr perpendicular magnetic film is described in Japanese Patent Laid Open Specification No. (Kokai No.) 58-164018, "METHOD FOR MANUFACTURING A PERPENDICULAR MAGNETIC RECORDING MEDIUM", published on Sept. 28, 1983, and in Journal of Magnetism and Magnetic Materials 35 (1983) 286-288, "PERPENDICULAR ANISOTROPY IN Co-Cr FILMS".

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  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Magnetic Record Carriers (AREA)
US06/685,838 1983-12-27 1984-12-24 Perpendicular magnetic recording medium Expired - Fee Related US4725482A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP58249983A JPS60138720A (ja) 1983-12-27 1983-12-27 垂直磁気記録媒体
JP58-249983 1983-12-27

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US07/139,823 Division US4824539A (en) 1983-12-27 1987-12-30 Perpendicular magnetic recording medium

Publications (1)

Publication Number Publication Date
US4725482A true US4725482A (en) 1988-02-16

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US06/685,838 Expired - Fee Related US4725482A (en) 1983-12-27 1984-12-24 Perpendicular magnetic recording medium
US07/139,823 Expired - Fee Related US4824539A (en) 1983-12-27 1987-12-30 Perpendicular magnetic recording medium

Family Applications After (1)

Application Number Title Priority Date Filing Date
US07/139,823 Expired - Fee Related US4824539A (en) 1983-12-27 1987-12-30 Perpendicular magnetic recording medium

Country Status (4)

Country Link
US (2) US4725482A (enrdf_load_stackoverflow)
JP (1) JPS60138720A (enrdf_load_stackoverflow)
DE (1) DE3447505A1 (enrdf_load_stackoverflow)
GB (1) GB2153391B (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4891114A (en) * 1986-12-31 1990-01-02 Basf Aktiengesellschaft Magnetic recording media
US4911810A (en) * 1988-06-21 1990-03-27 Brown University Modular sputtering apparatus
US5009762A (en) * 1988-07-08 1991-04-23 Oki Electric Industry Co., Ltd. Magneto-optical recording medium having protective film with increased kerr effect and improved protection characteristic and manufacturing method of the same
US5059468A (en) * 1986-03-29 1991-10-22 Canon Kabushiki Kaisha Magnetic recording medium
US5132173A (en) * 1989-02-10 1992-07-21 Canon Kabushiki Kaisha Magnetic recording medium having a silicon oxide protective layer with an electrical specific resistance of from 3.3×1013 to 5.0×15 ohm.cm
US5633739A (en) * 1994-11-07 1997-05-27 Hitachi, Ltd. Color liquid crystal display device composed of color filter with a layer of three primary color array patterns fabricated by thermal dye transfer technology

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4761334A (en) * 1984-09-21 1988-08-02 Kabushiki Kaisha Toshiba Magnetic recording medium
US4729924A (en) * 1984-12-21 1988-03-08 Minnesota Mining And Manufacturing Company Metallic thin film magnetic recording medium having a hard protective layer
US4798765A (en) * 1985-03-28 1989-01-17 Victor Company Of Japan Ltd. Perpendicular magnetic recording medium
DE3610431A1 (de) * 1985-03-28 1986-10-02 Victor Company Of Japan, Ltd., Yokohama, Kanagawa Quermagnetisierungsaufzeichnungsmedium
US4803577A (en) * 1985-06-12 1989-02-07 Tdk Corporation Vertical magnetic recording system using rigid disk
US5055351A (en) * 1987-10-15 1991-10-08 Canon Kabushiki Kaisha Metal thin film type magnetic recording medium
DE3803000A1 (de) * 1988-02-02 1989-08-10 Basf Ag Flaechenfoermiges, mehrschichtiges magneto-optisches aufzeichnungsmaterial
EP0399848A3 (en) * 1989-05-25 1991-03-27 Hitachi Maxell Ltd. Magnetic recording medium and method of manufacturing the same
US5316844A (en) * 1990-04-16 1994-05-31 Hoya Electronics Corporation Magnetic recording medium comprising an aluminum alloy substrate, now magnetic underlayers, magnetic layer, protective layer, particulate containing protective layer and lubricant layer
US5078846A (en) * 1990-08-14 1992-01-07 Seagate Technology, Inc. Process for forming hafnia and zirconia based protective films on longitudinal magnetic recording media
GB2254620B (en) * 1991-03-25 1994-10-05 Kobe Steel Ltd Manufacturing method of magnetic disk
JPH0896339A (ja) * 1994-09-22 1996-04-12 Sony Corp 磁気記録媒体
JP3274615B2 (ja) * 1996-03-08 2002-04-15 日本アイ・ビー・エム株式会社 垂直磁気記録媒体及びそれを用いた磁気記録装置
US6589676B1 (en) * 2000-07-25 2003-07-08 Seagate Technology Llc Corrosion resistant magnetic thin film media

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3498837A (en) * 1967-01-11 1970-03-03 Ibm Vacuum coating chromium-chromium oxide on recording member
US4268369A (en) * 1977-07-18 1981-05-19 Ampex Corporation Process of making silicon dioxide films for use as wear resistant coatings in video and digital magnetic recording
US4272563A (en) * 1976-02-27 1981-06-09 Basf Aktiengesellschaft Manufacture of magnetic recording media having a wear-resistant surface
US4307156A (en) * 1978-06-13 1981-12-22 Nippon Electric Co., Ltd. Magnetic record member
US4390562A (en) * 1980-05-06 1983-06-28 Nippon Electric Co., Ltd. Process of manufacturing a magnetic record member
US4454195A (en) * 1981-08-27 1984-06-12 Tdk Electronics Co., Ltd. Magnetic recording medium
US4495242A (en) * 1981-04-02 1985-01-22 Fuji Photo Film Co., Ltd. Magnetic recording medium
US4537832A (en) * 1982-12-25 1985-08-27 Tdk Corporation Magnetic recording medium
US4565734A (en) * 1983-03-18 1986-01-21 Fuji Photo Film Co., Ltd. Magnetic recording medium
US4581245A (en) * 1981-12-24 1986-04-08 Nihon Shinku Gijutsu Kabushiki Kaisha Method of manufacturing of abrasion resisting magnetic recording product
US4675240A (en) * 1982-11-22 1987-06-23 International Business Machines Corporation Magnetic recording disk using silicon substrate

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2126887C3 (de) * 1971-05-29 1981-11-19 Ibm Deutschland Gmbh, 7000 Stuttgart Niederschlagen magnetisierbarer Schichten durch Kathodenzerstäubung
US4124736A (en) * 1974-10-29 1978-11-07 Poly-Disc Systems, Inc. Surface protected magnetic recording members
GB1599161A (en) * 1976-07-15 1981-09-30 Matsushita Electric Ind Co Ltd Magnetic recording medium and method of making the same
JPS57176537A (en) * 1981-04-21 1982-10-29 Canon Inc Magnetic recording medium
JPS58164018A (ja) * 1982-03-24 1983-09-28 Sharp Corp 垂直磁気記録媒体の製造方法
JPS59119538A (ja) * 1982-12-25 1984-07-10 Tdk Corp 磁気記録媒体
DE3343107A1 (de) * 1983-11-29 1985-06-05 Basf Ag, 6700 Ludwigshafen Magnetische aufzeichnungstraeger

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3498837A (en) * 1967-01-11 1970-03-03 Ibm Vacuum coating chromium-chromium oxide on recording member
US4272563A (en) * 1976-02-27 1981-06-09 Basf Aktiengesellschaft Manufacture of magnetic recording media having a wear-resistant surface
US4268369A (en) * 1977-07-18 1981-05-19 Ampex Corporation Process of making silicon dioxide films for use as wear resistant coatings in video and digital magnetic recording
US4307156A (en) * 1978-06-13 1981-12-22 Nippon Electric Co., Ltd. Magnetic record member
US4390562A (en) * 1980-05-06 1983-06-28 Nippon Electric Co., Ltd. Process of manufacturing a magnetic record member
US4495242A (en) * 1981-04-02 1985-01-22 Fuji Photo Film Co., Ltd. Magnetic recording medium
US4454195A (en) * 1981-08-27 1984-06-12 Tdk Electronics Co., Ltd. Magnetic recording medium
US4581245A (en) * 1981-12-24 1986-04-08 Nihon Shinku Gijutsu Kabushiki Kaisha Method of manufacturing of abrasion resisting magnetic recording product
US4675240A (en) * 1982-11-22 1987-06-23 International Business Machines Corporation Magnetic recording disk using silicon substrate
US4537832A (en) * 1982-12-25 1985-08-27 Tdk Corporation Magnetic recording medium
US4565734A (en) * 1983-03-18 1986-01-21 Fuji Photo Film Co., Ltd. Magnetic recording medium

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Journal of Magnetism and Magnetic Materials 35, (1983) 286 288. *
Journal of Magnetism and Magnetic Materials 35, (1983) 286-288.

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5059468A (en) * 1986-03-29 1991-10-22 Canon Kabushiki Kaisha Magnetic recording medium
US4891114A (en) * 1986-12-31 1990-01-02 Basf Aktiengesellschaft Magnetic recording media
US4911810A (en) * 1988-06-21 1990-03-27 Brown University Modular sputtering apparatus
US5009762A (en) * 1988-07-08 1991-04-23 Oki Electric Industry Co., Ltd. Magneto-optical recording medium having protective film with increased kerr effect and improved protection characteristic and manufacturing method of the same
US5132173A (en) * 1989-02-10 1992-07-21 Canon Kabushiki Kaisha Magnetic recording medium having a silicon oxide protective layer with an electrical specific resistance of from 3.3×1013 to 5.0×15 ohm.cm
US5633739A (en) * 1994-11-07 1997-05-27 Hitachi, Ltd. Color liquid crystal display device composed of color filter with a layer of three primary color array patterns fabricated by thermal dye transfer technology

Also Published As

Publication number Publication date
GB2153391B (en) 1987-04-29
GB8432627D0 (en) 1985-02-06
DE3447505C2 (enrdf_load_stackoverflow) 1989-06-29
DE3447505A1 (de) 1985-07-11
JPS60138720A (ja) 1985-07-23
GB2153391A (en) 1985-08-21
US4824539A (en) 1989-04-25

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